His proposals, which combined political-military strategies with eschatological elements, along with his origin and enigmatic personality, remain partially understood.
Reubeni managed to secure an audience with king John (João) of Portugal in November 1525, supported by a letter of recommendation from Pope Clement VII.
Gedaliah ibn Yahya ben Joseph speaks of him as being "a man of dark complexion, like a Negro, and of low stature," his place of origin remains a mystery.
[3] Ibn Yahya elaborates, furthermore, that when David Reubeni visited Portugal, he stood in need of interpreters who escorted him in his journey, since he was only familiar with the Hebrew and Arabic languages.
[4] He related that he had been sent by his brother, King Joseph, who ruled the kingdom with seventy elders, who was seeking alliances against the Turks conquering the area for its great wealth.
Another version is that his true origin was at a port called Cranganore, along the Malabar Coast of India, where a large and well-organized Jewish community had lived for many centuries.
In Rome, with the help of a Jewish friend, he laid out his detailed plans before the Pope, who had said to him that he could not personally get involved in helping to build such a coalition, but nevertheless referred David Reubeni to John (João), the king of Portugal, who was directly related to King Charles by virtue of his marriage with his sister.
Acquiescing, David Reubeni then set sail from Italy for Portugal, accompanied with a brief and letters of recommendation from the Pope to help facilitate his errand.
[2] He left Khaibar on December 8, 1522, travelled ten days' journey until he reached the port of Jedda, crossed the Red Sea and disembarked from his boat in the city of Suakim in the country of the blacks.
He then joined a camel caravan which took him northbound, following the Nile River along the Nubian desert in northern Sudan, during which time he had disguised his identity by dressing as a Muslim and claiming to be a descendant of Muhammad.
He eventually reached Cairo (where his Jewish host was reluctant to receive him in his house because of his Muslim appearance), Gaza, Hebron (where he visited the tomb of the Patriarchs) and Jerusalem.
To the latter he told a tale of a Jewish kingdom ruled over by his brother Joseph Reubeni in Arabia, where the sons of Moses dwelt near the Sambation River.
Jewish people raised money privately to give to Reubeni for his travel to Almeirim, the residence of King John III of Portugal, which he reached in November 1525.
Reubeni's striking appearance–a swarthy dwarf in Oriental costume–and messianic claims attracted the attention of Diego Pires, a descendant of conversos and a secretary to the High Court of Appeals of Portugal.
He probably died there, as Herculano reported that "a Jew who came from India (sic) to Portugal" was burned at an auto da fé at Évora in 1541.